borisk
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Posts: 6
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Hi,
I'm encountering the same problem. It seems to me that for oscillator phase noise for instance, you set the noise type to sources, and when you run pnoise there will be a phnoise option. This is I think the total noise, i.e., AM and PM, but luckily in oscillators the PM dominates such that when you look at phnoise it'll correspond to the PM component. The other thing to keep in mind is that it is in the form of voltage noise, but the PSD's of the voltage noise process and the phase noise process are related.
Anyway, back to the question. If looking at the divider or even simply inverters and such, we want the jitter and in this case, if you set the noise type to sources and check the phase noise it's much higher than expected. Here the AM dominates the PM, and again, the phnoise gives them combined in terms of voltage.
You can set the noise type to modulated and you'll be able to see the AM and PM contributions separately. I think that here we want to look at the PM only which turns out to be generally smaller (at least for some buffers I was looking at). What I don't know is whether the AM --> PM conversion, say from a noisy input, is captured correctly by this.
Any other comments? What about setting noise type to timedomain or jitter?
Cheers,
Boris
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